I am BEGGING Jet Blue to come to Atlanta.
Southwest is no replacement for Airtran. I loved Airtran, but hate Southwest. Jet Blue is much closer to Airtran's product than is Southwest. I think there's a real market for them here: people like me who liked Airtran and don't want to switch to DL or WN.
I think some west coast routes and ATL-BOS are do-able. Maybe even JFK. I would actually pay a few $ more to go JetBlue and avoid DL and WN.